Phelps, 30, will be assisting his longtime coach Bob Bowman, who took over the Sun Devils’ program earlier this year, according to the Arizona Republic.

Bowman was also named head coach of the 2016 U.S. men’s Olympic swim team. Phelps followed his mentor to Tempe to continue training for the Rio Games. He’s expected to retire again whether he makes the team or not.

Phelps has won more medals in the history of the modern games with 22. Of those, 18 were gold. He briefly quit the sport after the 2012 London Games.

The 6-foot-4 swimmer from Baltimore is no stranger to the Valley. He made his official return to competition at Mesa’s Skyline Aquatics Center during the 2014 Arena Grand Prix.

The five-time Olympian also came back at the Mesa event in April from a six-month suspension for a DUI.